Automatic antiknock rating and adjustment apparatus

ABSTRACT

AUTOMATIC ANTIKNOCK MONITORING AND/OR ADJUSTING APPARATUS HAVING DETONATION TESTING ENGINE OPERATED ON FUEL TO BE MONITORED OR ADJUSTED, AND AUTOMATIC CONTROLS TO CHANGE ITS COMPRESSION RATIO IN RESPONSE TO CHANGES IN DETONATION INTENSITY, WITH OCCASIONAL RESETTING AGAINST RESULTS USING A REFERENCE FUEL. MAXIMUM KNOCK FUEL-AIR RATIO IS USED AND THE AUTOMATIC CONTROLS CAN ALSO CONTROL THE ADDITION OF HIGH ANTIKNOCK BLEND INGREDIENT TO THE FUEL.

Sept. 12, 1972 J. T. JONES ETAL AUTOMATIC ANTIKNOCK RATING ANDADJUSTMENT APPARATUS Filed Dec. 19, 1969 8 Sheets-Sheet l HOL HOLJdU-Ov:

INVENTORS John, T. Jones, William, C. L ud & HudsomWKellogg Sept. l2,1972 J. T. JONES ETAL AUTOMATIC ANTIKNOCK RATING AND ADJUSTMENTAPPARATUS 8 Sheets-Sheet 2 Filed Dec. 19, 1969 w 5&7.. l,

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AUTOMATIC ANTIKNOCK RATING AND ADJUSTMENT APPARATUS Filed Dec. 19, 19698 Sheets-Sheet 4 INVENTORS John -I Jones, Wilhelm C.L ud 8(Hudson/Wk'ellogg 5Pt- 12 1972 J. T. JONES ETAL 3,690,851

AUTOMATIC ANTIKNOCK RATING AND ADJUSTMENT APPARATUS Filed Dec. 19, 19698 Sheets-Sheet 5 Fray/L ef rl/ mk@ mpllfe" wh, Rechfier" `mLyrsN'roRs.7'. ones Walfvlfuno. 1: mit Hudson W1( 611129? Sept. 12, 1972 .1. T.JONES ETAL 3,690,851

AUTOMATIC ANTIKNOCK RATING AND ADJUSTMENT APPARATUS Filed Dec. 19, 1969s sheets-sheet e MC1 @acc Dec reces@ ,l Axe/Lars Lll 95% Alg@ TNVENTORSJohn rBlanes, William C. L ud L Hudson, W. Kellogg Sept. l2, 1972 J. T.JONES ET AL AUTOMATIC ANTIKNOCK RATING AND ADJUSTMENT APPARATUS FiledDec. 19, 1969 8 Sheets-Sheet '7 INVENTORS JOHN TJONES WILLIAM c. LUD T8"HUDSON W. KELLOQ* SPt- 12 1972 J. 1'. JONES ETAL AUTOMATIC ANTIKNOCKRATING AND ADJUSTMENT APPARATUS 8 Sheets-Sheet 8 Filed Dec. 19, 1969INVENTORS w@ n@ +r. l I I J Jo/ML TJones, WLZ

am GLLLcLt r Hudson #lifted/w United States Patent O 3,690,851 AUTOMATICANTIKNOCK RATING AND ADJUSTMENT APPARATUS John T. Jones, Ardsley,William C. Ludt, Yonkers, and Hudson W. Kellogg, Dobbs Ferry, N.Y.,assignors to Ethyl Corporation, New York, N.Y. Continuation-impart ofapplication Ser. No. 617,754, Jan. 24, 1967, now Patent No. 3,485,598,which is a continuation-impart of applications Ser. No. 205,015, June25, 1962, now Patent No. 3,383,904, Ser. No. 299,583, Aug. 2, 1963, andSer. No. 377,192, .lune 23, 1964. This application Dec. 19, 1969, Ser.No. 886,458

Int. Cl. C10k 3/00 U.S. Cl. 44-2 22 Claims ABSTRACT OF THE DISCLOSUREAutomatic antiknock monitoring and/or adjusting apparatus havingdetonation testing engine operated on fuel to be monitored or adjusted,and automatic controls to change its compression ratio -in response tochanges in detonation intensity, with occasional resetting againstresults using a reference fuel. Maximum knock fuel-air ratio is used andthe automatic controls can also control the addition of high antiknockblend ingredient to the fuel.

The present application is a continuation of application Ser. No.617,754 filed Ian. 24, 1967 (U.S. Pat. 3,485,- 598, granted Dec. 23,1969), which in turn is a continuation-in-part of applications Ser. No.377,192 filed June 23, 1964; Ser. No. 299,583 filed Aug. 2, 1963 (nowabandoned); and Ser. No. 205,015 filed June 25, 1962, now U.S. Pat.3,383,904 granted May 21, 1968.

The present invention relates to the measurement and adjustment ofantiknock ratings of fuels such as gasoline.

Among the objects of the present invention is the provision of novelapparatus for automatically adjusting the antiknock rating of the abovetype of fuels.

The foregoing as well as additional objects of the present inventionwill be recognized from the following description of several of itsembodiments reference being made to the accompanying drawings wherein:

FIG. 1 is a schematic representation of an antiknock rating apparatusaccording to the present invention;

FIG. 2 is a generally diagrammatic view of the mechanical elementssuitable for use in the apparatus of FIG. l, showing a test engine andsome of its related structures;

FIG. 3 is a partially schematic more detailed illustration of one formof an assembly of components that cooperate as in FIG. l, to form anautomatic rating apparatus representative of the present invention;

FIG. 4 is a circuit diagram of one form of deviationreducing control forthe apparatus of FIGS. 1 and 2;

FIG. 5 is an enlarged plan view of one of the controls of FIG. 3;

FIG. 6 is a side view of the control of FIG. 5;

FIG. 7 is a more detailed illustration of an auxiliary unit in theconstruction of FIG. 3;

FIG. 8 schematically shows another form of assembly illustrative of thepresent invention.

FIG. 9 schematically shows another form of control unit suitable for usein accordance with the persent invention;

FIG. 10 is a schematic representation of a modified control unit inaccordance with the present invention;

FIG. 1l is a detailed illustration of an adjusting assembly typicalofthe present invention; and

FIG. 12 shows a modified adjusting assembly pursuant to the presentinvention.

According to the present invention an automatic apparatus is providedfrom monitoring and/or adjusting the ice knock rating of a fuel streamin a fuel supply system such as in a gasoline refinery. For example theinvention can take the form of a blending apparatus for automaticallyproducing a stream of blend fuel that has a substantially uniformantiknock rating, said apparatus including a detonation testing engine,a measuring system connected to indicate the intensity of detonationknocking that takes place in the engine and adjusting mechanismconnected for automatically adjusting the compression ratio of theengine to keep the detonation intensity at a predetermined value,sampling means connected to receive samples of blend fuel and deliverthem to the engine for combustion therein at maximum knock fuel-airratio, the sampling means being further connected to deliver to theengine samples of a reference fuel for combustion therein at maximumknock fuel-air ratio, the adjusting mechanism being connected to causethe sampling means to automatically shift from one fuel to the other andback again, and automatic control structure connected to the measuringsystem to control the blending of the stream so as to have thecompression ratio of the engine when operated on the blend fuel at apredetermined value based on the compression ratio when operated on thereference fuel.

For best results the apparatus is'arranged to automatically switch thefuel supply to the test engine periodically so that the test engine willoperate on a standard reference fuel suiciently frequently that anydeparture in the operation of the engine can be promptly detected andcompensated for. The sampling means can be connected to automaticallyshift the engine to the referenced fuel whenever the control actionexceeds a predetermined limit. It is also preferred to have the controlstructure directly respond to changes in compression ratio rather thanchanges in detonation intensity.

A feature of the present invention is the inclusion in the monitoring orcontrol apparatus of an automatic arrangement for adjusting thefuel-sampling means to the condition in which the fuel it delivers tothe engine is at its maximum knock fuel-air ratio, and to then hold thesampling means in that condition.

Another feature of the present invention is that it can use a testengine and a detonation measuring system, both of which are standardoctane rating items, so that the apparatus provides results that closelyconform with standard specifications. Best results are also obtainedwhen a temperature control such as cooling means is included in theapparatus to cool the fuel supplied to the engine or compensate forheating of the fuel caused by the apparatus or other sources.

The automatic arrangement for bringing the fuel-air ratio to maximumknock value desirably goes through an automatic sequence in which itfirst adjusts only the compression ratio of the engine to bring thedetonation intensity to a predetermined value, then adjusts only thefuel-air ratio for the fuel on which the engine operates so that it isat the maximum knock ratio, and finally continues to operate byadjusting only the compression ratio.

The maximum knock-adjusting sequence can be arranged to take place oncein a measurement and/or control operation, after which the compressionratio can be automatically adjusted without further fuel-air ratiochanges. In addition the sequence is particularly effective if thefuel-air ratio adjustment is carried out by first reducing that ratio toa very low value and then increasing the ratio in small increments untilthe knock intensity just goes through a maximum.

Referring to the drawings, the apparatus of FIG. l includes a testengine indicated at 10 which can be of the standard type such asillustrated and described in the 1960 ASTM Manual for RatingAFuels byMotor and Research Methods, published by the American Society forTesting and Materials, Philadelphia, Pa. Such a convenf tional enginecan be and is frequently equipped with an actuator 12 for changing itscompression ratio, which actuator is in the form of a reversibleelectric motor. The apparatus of FIG. 1 is further provided 'with asecond actuator 14 for changing the fuel-to-air ratio of the combustionmixture applied to the test engine. Actuator 14 can also be electricallyoperated as by means of a reversible electric motor.

As in the usual test engine construction, a detonation pick-up 16 isprovided so as to develop an electrical signal varying in intensity inaccordance with the intensity of the detonation or knock that occursduring the operation of the test engine. In the apparatus of FIG. 1 thesignals so produced are delivered to an amplifier and deviation computer'18 which amplifies the signals and also determines how far thedetonation or Iknock varies from some predetermined value. If desiredthe amplified signal can be displayed on a meter such as the usualknockmeter 20. In addition a recorder 22 may be used to make a record ofthe signals, either indicative of the degree of knock or of thedeviation from the predetermined knock intensity, or both. Recorders ofthis type are well-known and will make records on circular orrectangular charts, usually with a moving pen actuated by the electricsignal being recorded as well as by a timing mechanism that moves thechart.

'I'he automatic testing of the present invention is effected by acombination of a deviation-reducing control .24, a knock-maximizingcontrol -26 and a sequencer 2-8. The deviation-reducing control 24 issupplied with signals from the deviation computer 18 and is connected tocompression ratio change actuator 12 so as to change the compressionratio in the direction which reduces the difference between a pre-setknock intensity and the knock intensity indicated by the detonationpick-up. The knockmaximizing control 26 is supplied with signals fromthe amplifier 18 or the detonation pick-up 16, and in turn is connectedto the fuel-air ratio change actuator 14. Sequencer 28 is connected tooperate the two controls 24 and 26 in the appropriate sequence. At thecompletion of the testing sequence the antiknock rating can be read froman indicator 30 which is conveniently operated by the compression ratiochange actuator 1-2. When operating at the fuel-air ratio for maximum-knock intensity, each fuel has one specific compression ratio at whichit will produce a standard -knock intensity and this compression ratiodetermines the antiknock rating of that fuel. For ratings up to andincluding 100, the rating signifies the percentage of iso-octane(2,2,4-trirnethylpentane) in a mixture of the iso-octane with normalheptane, which mixture develops the same standard knock intensity undermaximum knock conditions at that compression ratio. For fuels havingantiknock ratings above 100, the rating similarly represents thecompression ratio at which the standard knock intensity is developedunder maximum knock conditions by mixtures of iso-octane with tetraethyllead rather than mixtures of iso-octane with normal heptane.

Indicator 30 can show both the antiknock rating and the correspondingcompression ratio, or it can show merely one or the other of thesevalues. Antiknock ratings have a standard relationship to the finalcompression ratios, as indicated for example in Table V on p. 21 of theabove manual.

For convenience in making preliminary or intervening adjustments ofcompression ratio, the construction of FIG. 1 can include a manualcontrol 32 such as a simple three-position switch for energizingactuator 12 in one direction or the other, or for setting the actuatorso that it is controlled only by the deviation-reducing control 24. Asimilar manual control 33 can be used for fuelair ratio changes.

FIG. 2 illustrates the interrelationship between the test engine 10,actuating motor 12 for changing the compression ratio of the engine, andactuating motor 14 for changing the fuel-air ratio. Engine 10 is of theconventional construction with its cylinder 34 movable to and fro alongits cylindrical axis. Near the base of the cylinder it is provided withexternal thread 36 that meshes with internal thread on a rotary nut 38which is in turn accurately supported so that it does not show anymovement in the direction of the cylindrical axis. However, the nut 38can rotate around that axis and is rotatably driven to and fro in thatdirection by a worm 40 that meshes with external threads 42 on the nut38. Worm 40 is in turn driven -by the motor 12 as by means of drivecoupling 44 and speed reducing gear box 46. Indicator 30 can also beconnected to be driven by worm 40 as by means of the flexible driveshaft 48.

The intake line E50 for engine 10- has the usual venturi 52 with a fueldischarge tube 54 leading to and opening in the venturi throat. A fixedfuel level sight glass 56 is shown as in communication with the fueldischarge tube 54 for convenience in reading the height of the fuellevel, although such reading is not needed for automatic operation inaccordance with the present invention. Flexible conduit 58 connects thefuel discharge tube 54 with a carburetor bowl 60 having avalve-controlling float 62 that determines the level of the fuel inwhich the oat is immersed. The carburetor bowl 60 is provided with anarm 64 containing a vertical passageway that is internally threaded andthreadedly engaged on a vertically disposed externally threaded shaft 66journaled at its ends in a frame 68. One end of the threaded shaft 66 isconnected for rotation by motor 14, and the shaft itself is so supportedthat it cannot move vertically. Frame 68 is also arranged to guide arm64 so that the arm carries the carburetor bowl upwardly or downwardly,depending upon which way motor 14 rotates, without permitting the arm totilt or swing. The higher the float controlled fuel level with respectto the venturi 52, the richer the fuelair ratio of the mixture deliveredto intake line 50.

The usual detonation pick-up 70 is mounted in the head or top of thetest engine 10 so that the pick-up has its sensing element exposed tothe combustion chamber 72 of the engine. The sensing element can be asimple piezoelectric transducer that generates an electrical signal whensubjected to pressure or rate of pressure change, and modulates thesignal so that it follows the change in pressure or in rate of pressurechange. Knocking or detonation during engine operation causesdevelopment of pressures higher than for normal combustion and rates ofpressure change in excess of those for normal combustion, and theelectrical signal corresponding to these high pressures or high rates ofpressure change can be readily distinguished. A11 amplifier 74 similarto'that ordinarily used, can be arranged to amplify the electricalsignals and make them suitable for reading by knock-meter 20. Amplifier74 corresponds to the amplifier noted in FIG. 1 as an integral portionof unit 18.

FIG. 3 illustrates an automatic octane rating apparatus of the inventionin which a deviation computer and portions of a knock maximizing controlare combined in a single unit which can also include the deviationreducing control shown in FIG. 4. Unit 90 is built around a recordersuch as the ElectroniK l7 strip chart model available fromMinneapolis-Honeywell Regulator Company and described in its instructionmanual numbered 367001. The recorder has the usual chart that is fedfrom a. supply roll to a take-up roll at a constant speed, and a penthat is traversed across the chart in accordance with variations inelectrical signals delivered to an input terminal. These features arewell known and since they are not essential parts of the presentcombination, are not illustrated. 'I'he recorder is also equipped with acontrol slide wire represented at 94 in FIG. 4, that has its wiper ortap 96 moved in accordance with movements of the pen so as to set up acontrol point having a potential intermediate between that across theends of this slide wire.

Movement of the pen and tap 96 is effected with the help of pulley 98,and for the purposes of the present invention this pulley is providedwith an actuator bar 100 that turns with it and is located so as toclose either of a pair of switches 101, 102 when the pulley rotatessufficiently far in either direction. Switch 101 is shown as a low limitswitch, and switch 102 as a high limit switch.

Unit 90 is under the control of a sequencer 110 that includes a gangedset of stepping switches 112 driven by a solenoid ratchet stepper 114.Six wafertype switch segments, identied as A, B, C, D, E and F, are inthis ganged set along with a set of Ibreaker contacts 116, 118 operatedby cam 120. Wafer 112A has a central electrically conductive contactdisc 122 rotated by shaft 124 common to all the switch segments, and ithas a notch 126 at one portion of its periphery. A wiper or brushcontact 128 is fixed and remains in electrical connection with the discthroughout its rotation so as to provide a tixed terminal for electricalconnection to that disc. Around the periphery of wafer 112A are sevenxed terminals numbered 1, 2, 3, 4, 5, 6 and 7, each projecting centrallyso that they come into wiping engagement with the disc as it rotates.Each terminal is, however, so dimensioned that when notch 126 is broughtinto opposition to it, the wiping end of the terminal will liecompletely within the notch 126 so that terminal becomes disconnectedfrom the disc.

Segments B, C, D, E and F can also be of the wafer type with sevensimilarly located terminals each, but in each of these a narrow arm 130is arranged to individually contact one of the terminals at a time asshaft 124 rotates. Arms 130 of each of the segments B, C, D, E and F areelectrically insulated from each other as well as from disc 122, andeach has its own lixed wiping contact 140.

Solenoid ratchet 114 is connected for energization by a DC source ofcurrent such as rectifier 150 which is shown connected through hot lead151 and grounded lead 152 to a plug 154 that can be inserted in aconventional 110 volt AC power line receptacle. Fuse 156 and on-otswitch 158 can also be included in this circuit.

The sequencer also includes a delay relay generally indicated at 160 forthe deviation reducing control and another delay relay 170 for the knockmaximizing control. Relay 170 operates in conjunction with aninterrupter 180 as well as with delay switches 178 and 179.

Delay relay 160 has three switch armatures 161, 162 and 163 illustratedin the normal position which they take when this relay is not energized.In these positions the armatures engage back contacts. When relay 160 isenergized it immediately pulls its armatures over so that they eachengage front contacts and this operation is completed without any delay.However, when the relay is decnergized the armatures will lbe heldagainst their front contacts for a period of about one minute before thearmatures are released from their front contacts and permitted to fallback to their back contacts. A dash pot 164 is illustrated as providingthe above delay, but any other form of delay mechanism can be used ifdesired.

Relay 170 is operated in the same manner, a delay dash pot being hererepresented at 174. A pair of armatures 171, 172 forming part of relay170 are shown in the normal position they take when this relay is notenergized. Winding 173 of relay 170 is energized from either of a pairof parallel leads 184, 186, and in series in lead 184 is the delayswitch 179 which is of the normally closed type that stays closed untilabout twenty seconds or so after power is supplied to lead 184. Thistype of operation is supplied by means of a heater 188 which forms partof switch 179, in combination with a switch arm 190 of bimetallic naturelocated so as to be warmed by the heater 188 to the degree required tosnap open after the heat has been on for the above period of time.

Switch 178 is of the normally open type, the switch terminals beingconnected to leads 191, 192, and the heater being separately connectedto lead 193.

The sequencer of FIG. 3 also has a reset or start 6 switch 200 with twoarmatures 201, 202 mechanically biased to the illustrated position as bya spring, not shown. In this position armature 201 is out of engagementwith a pair of contacts 211, 212, but armature 202 is in engagement withits two contacts 221, 222.

IIt is also desirable to connect a capacitor 230 across the DC outputterminals 231, 232 of rectifier 150, and to connect a resistor 240 andcapacitor 242 in series between terminal 232 and solenoid lead 244 withwhich terminal 232 is intermittently connected by the switchingarrangement.

Pulley 98 of unit 90 has, in addition to the low and high limit switches101, 102, mechanical maximum sensing elements that include a maximumswitch 250 with an actuating nose 252 biased outwardly and holding thisswitch in open position. Maximum switch 250 (FIG. 5) is xed on a plate254 which in turn is pivotally secured to a stationary support 256.Mounting screw 258 passes through an aperture in plate 254 and through abushing 260, and is threadedly engaged in support 256. This mountingscrew arrangement permits plate 254 to pivot and also frictionallyengages the plate suiciently to keep it from pivoting unless it isrotated by a force of sufficient magnitude. A iiat or arched springfriction washer 262 can be inserted between bushing 260 and plate 254 orbetween the head of the mounting screw 258 and plate 254, to improve thefrictional engagement.

`Pivoting of the plate is effected by a pin 264 secured to the face ofthe pulley 98 and arranged to engage the switch 250 as the pulley 98rotates. A cam lobe 266 in plate 254 cooperates with pin 264 to pull theplate in clockwise direction around its mounting screw as seen in FIG.5, when the pulley 98 rotates an appreciable distance incounterclockwise direction around its pivot. This clockwise pivoting ofplate 254 helps bring switch 250 closer to the pin so that the pin willnot have as far to travel when it returns from a counterclockwiseexcursion. Because the tilting of plate 254 can position switch nose 252at varying distances from the center of pulley 98, an auxiliarycontactor 268 can be used to cover nose 252 and provide engagement forpin 264 regardless of the tilt of plate 254. Auxiliary contactor 268 canbe journaled on a pivoted bar 270.

Indicator lights 280 can also be used to show the condition of theapparatus, and a capacitor 282 can be connected between the ungroundedends of the drive windings for motor 14.

The various leads in the sequencer of FIG. 3 are connected as follows:

Terminal 1 of switch segment A to terminal 212. Terminal 2 of switchsegment A to terminals 1 and 2 of switch segment C and to tirst end ofhigh switch 102. Terminal 3 of switch segment A to back contact forarmature 162.

Terminal 4 of switch segment A to first end of low switch 101.

Terminal 5 of switch segment A to lead 191. Terminal 6 of switch segmentA to terminals 5 and 6 of switch segment C.

Terminal 7 of switch segment A to back contact for armature 163.

Center contact of switch segment A to lead 244 (through breaker points116, 118).

Terminals 1, 2 and 5 of switch segment B to terminal Terminal 3 ofswitch segment B to second end of low switch 101.

Terminal 4 of switch segment B to back contact for armature 171.

Terminal 6 of switch segment B to armature 163.

Center contact of switch segment B to terminal 211 and second end ofhigh switch 102. Center contact of switch segment C to front contact forarmature 162.

Terminals 1 and 5 of switch segment D to winding of relay 160.

Terminal 3 of switch segment D to carburetor motor (loweringconnection).

Terminal 4 of switch segment D to lead 184, armature 172, one terminalof motor of interrupter 180, and one of the interrupter terminals ofinterrupter 180.

Center contacts of switch segments D and E to power supply lead 151.

Terminals 2, 3, 4, 6 and 7 of switch segment E to indicator lights 280.

Terminal 4 of switch segment F to carburetor motor (rising connection).

Center contact of switch segment F to lead 186 and rst end of maximumswitch 250.

Second terminal of interrupter 180 to second end of maximum switch 250.

Lead 193 to front contact for armature 172.

Armature 162 to terminal 221.

FIG. 4 illustrates a highly effective form of deviation reducing controlsimilar to that available commercially as Model IiP-102 DeviationProportional Pulse Control Relay of the Minneapolis-Honeywell RegulatorCo. As in this commercial model, the control of FIG. 4 has threethyratron tubes 301, 302, and 303 connected with discharge circuits anddischarge tripping circuits. Relays 310, 320 and 330 have their windingsin sereis in the respective discharge circuits. Relay 310 has threearmatures 311, 312, 313 and simultaneously moves all three toswitch-closing position when it is energized by a discharge in thyratron301. Such discharge is triggered by an adjustable grid circuit 341 andthe closing of the grid return circuit through armature 311 shorts outthe grid triggering voltage so that the discharge soon terminates.

Meanwhile similar grid triggering circuits 342 and 343 charge up thegrids of thyratrons 302 and 303 to their tiring voltage, and if thevoltage of tap 96 is different from that of tap 340 in a set point slidewire 345, one of these two thyratrons will have its grid voltage raisedsufficiently to tire while the other will be lowered a little and willnot tire.

Relay 320 is in the discharge circuit of the thyratron that tires whenthe voltage of the control slide wire tap is too high, and this relayactuates armatures 321, 322 and 323 from their normal positions, whichare illustrated, to their actuated positions in which they close acircuit supplying a pulse of power to decrease lead 351 from a powersupply lead 352. At the same time a similar increase signal lead has itsopen connection further opened to help assure that both increase anddecrease signals are not delivered simultaneously.

Conversely, when the relay 330 is energized, it actuates armatures 331,332 and 333, delivering a pulse of increase signal.

When the potentials of taps 96 and 340 are sufficiently close together,neither the thyratrons 302, 303 tire, and no signal is delivered to line351 or line 353. In any case, the shunting action of armatures 312, 313under the actuation of relay 310 resets the firing circuits ofthyratrons 302, 303 and prepares them for the next tiring trigger.

A feature of the above deviation reducing control is that the correctionpulses delivered to line 351 or 353 are longer when the taps 96 and 340are further apart in potential. As a result the corrections will muchmore rapidly bring the knock intensity to the standard value asdetermined by set point tap 340 and will do this with less hunting.

Typical circuit constants for the circuit of FIG. 4 are given in thedrawing (capacitances in microfarads and resistances in ohms) andprovide very effective results when used with thyratron plate suppliesat 270 AC volts and with grid potential supplies at 29 DC volts measuredat their recifier output capacitors. The potentiometer in the gridcircuit of thyratron 301 is preferably adjusted to produce a pulserepetition rate of about one per ten seconds, and the potentiometers inthe grid circuits of the other thyratrons adjusted so that thyratrons302 and 303 just barely miss firing when the control slide wire tap hasthe same potential as the set point slide wire tap and the thyratron 301fires. To help follow the operation of the circuit, indicator light 361,363 are connected in parallel with output leads 351, 353 and one ofthese will light whenever a correcting pulse is being delivered. Anotherlight 365 is connected to light when power is supplied to lead 352 andis available to pulsing armatures 321, 322, 331 and 332.

Manual control switches 368, 369 of the momentary contact type are alsoshown as provided to enable manual pulsing of increase and decreasesignals. An automatic disabling switch 370, preferably of the on-offtype that remains in the position to which it is moved, can also beinserted in lead 352.

The apparatus of FIG. 4 is interconnected in the combination of FIG. 3by having the power supply lead 352 of FIG` 3 switched on and offthrough armature 161 of relay 160 in FIG. 3. In addition anotherinterconnection 354 is used to energize relay 160 whenever a correctingpulse of either kind is delivered by the circuit of FIG. 4.

The assembly of FIG. 3 is placed in operation after connection to theappropriate power supplies, by operating reset switch 200 to bring thesequencer into position 1 (illustrated), after which this switch isreleased. When the sequencer is in any other position the action of thereset switch in closing a circuit between contacts 211, 212, completesan actuating circuit from rectifier output terminals 231, 232 to thesolenoid 114 through disc 122 of switch segment A and its terminal 1.The solenoid will accordingly rotate the selector one step clockwise asseen in FIG. 3. During this step breaker cam opens breaker points 116,118 until the step is completed. Holding reset switch 200 down will thusassure the stepping until selector reaches position 1 at which time thenotch 126 opens the circuit to terminal 1 of segment A and the actuationis terminated.

At the same time segment D of the sequencer as it reaches position 1completes a connection from power lead 151 through terminal 1 of thesegment to the winding of relay 160. This actuates relay which throughits armature 161 starts the correction action of the derivation reducingcontrol of FIG. 4. In the meantime the reset switch 200 is released andthis completes a supplementary energizing circuit for the solenoid 114from disc 122 through terminal 2 of segment A, terminal 1 of segment C,center contact of segment C, actuated armature 162, terminals 221, 222of the reset switch, terminal l'of segment B, center contact of segmentB, lead 233 and terminal 232. This steps the sequencer to position 2where the bulk of the correction action of the circuit of FIG. 4 iscompleted. At this position the notch 126 opens the above supplementalenergizing circuit to terminal 2 of segment A so that the sequencerremains in position 2.

During the dwell in position 2 the compression ratio of the engine isbrought by the deviation reducer of FIG. 4 to the value that produces adetonation signal corresponding to the predetermined standard as set byset-point tap 340. When the correspondence is sufficiently close, thedeviation reducer will not develop a correcting pulse in output lead 351or 353 and as soon as the time delay of relay 160 runs out, thearmatures of that relay return to their deenergized position (the one inwhich they are shown) and this closes a solenoid actuating circuit fromdisc 122, terminal 3 of switch segment A, armature 162, terminals 221,222 of reset switch 200, terminal 2 of switch segment B, center contactof switch segment B, and terminal 232. The solenoid accordingly steps toposition 3, where the notch 126 again opens the solenoid circuit.

In position 3 the relay 160 remains deenergzed but the switch segment Dcompletes a circuit that energizes the carburetor motor 14 and causes itto lower the carburetor. This lowering leans out the fuel mixture and asa result reduces the knock intensity. As the intensity becomes lower,pulley 9S rotates in counterclockwise direction as seen in FIG. 3, andit will soon bring its arm 100* around far enough to close low switch101. When this happens another solenoid energizing circuit isestablished from disc 122 through terminal 4 of switch segment A, lowswitch 101, terminal 3 of switch segment B, center contact of segment B,and terminal 232. This steps the solenoid to position 4 where notch 126again stops it.

In position 4 the downward rotation of carburetor motor 14 is stopped,and instead switch segments D and F establish an upward rotatingenergizing circuit for that motor through lead 151, center contact ofsegment D, terminal 4 of segment D, lead 184, normally closed delayswitch 179, lead 186, center contact of segment F and terminal 4 ofsegment F. The carburetor motor accordingly now raises the carburetorfor a few seconds until delay switch 179 opens circuitsrThis period ispreferably about twenty seconds.

As the carburetor is thus raised, the detonation intensity increases andpulley 98 is rotated clockwise bringing its pin 264 against the nose 252of switch 250, closing this switch. The closing of switch 250establishes a carburetor raising circuit as a shunt across delay switch179. This shunt branches otf from lead 184 through the contacts ofinterrupter 180 and the now closed maximum switch 250, and branches backto the center contact of segment F. Accordingly when delay switch 179times out, the carburetor continues to rise but now does so in aninterrupted manner, as for example moving up in 2 to 5 second stepsspaced by to 10 second intervals of no movement. This intermittentupward travel of the carburetor is continued as long as it causes theknock intensity to increase and the pulley 98 to move in clockwisedirection. When the maximum knock intensity is reached the pulley nolonger rotates, and at the next raising of the carburetor the knockintensity diminishes and the pulley 98 makes a very small return step incounterclockwise direction. This withdraws pin 264 from the maximumswitch and promptly permits that switch to return to its normally openposition, thus stopping further carburetor movement.

In the meantime delay relay 170 was energized through delay switch 179when the sequencer first reached position 4, and after delay switch 179open-circuited, this relay continued to be energized through lead 186each time the carburetor was driven upwards. Until maximum switch 250opens, the armatures 171, 172 of the delay relay 170 are accordinglyheld in actuated position. In this position they prepare a steptriggering energizing circuit for the solenoid 114, from terminal 4 ofswitch segment D to terminal 5 of switch segment A. This energizingcircuit is kept open initially by normally open delay switch 178, andafter that closes as a result of the heating action through actuatedarmature 172, actuated armature 171 keeps the circuit open. However,when the maximum switch 250 is opened, the relay 170 is no longerenergized and it times out, closing the solenoid energizing circuit. Theselector thereupon steps to position 5.

In position 5 switch segment D closes a circuit that actuates relay 160and also supplies energy for the deviation reducer to operate and adjustthe compression ratio of the engine. The actuation of armature 161cornpletes the energizing circuit for the deviation reducer, and at thesame time actuation of armature 162 closes a stepping circuit forsolenoid 114. This stepping circuit runs from disc 122 through terminal6 of switch segment A Terminal 5 of switch segment C, the center contactfor switch segment C, armature 162, terminals 221, 222, terminal 5 ofswitch segment B, the center contact of switch segment B, and terminal232. The sequencer accordingly promptly steps to position 6, but thisdoes not interfere with the continued operation of the deviationreducer. When relay 160 times out at the end of the new compressionratio search, its arms 163 completes a solenoid stepping circuit thatadvances the sequencer to position 7. This stepping circuit runs fromdisc 122 through terminal 7 of switch segment A, armature 163, terminal6 of switch segment B, the center contact for switch segment B, andterminal 232. In position 7 the measuring cycle is over and theapparatus does not function. It is ready, however, for another measuringcycle which can be initiated by merely operating reset switch 200 for amoment.

The compression ratio developed in step 6 need not be and generally isnot the same as the compression ratio reached while the sequencer is inposition 2, inasmuch as in position 6 the fuel-air ratio has beenbrought to maximum knock condition whereas at position 2 no maximumknock fuel-air ratio need have been present. The net result is that inposition 6 the compression ratio will be automatically brought to thesame value which would be arrived at through the standard ASTM processfor manually measuring antiknock ratings. In fact the automatic processof the present invention can even be considered more accurate in that iteliminates errors that may be inherent in the interpolation which ispart of the ASTM procedure. The maximum knock fuel-air ratio isgenerally the same when a fuel knocks at standard knock intensity, aswhen the fuel knocks at other intensities within a significant rangeabove and below standard intensity. It is accordingly unnecessary to gothrough any more fuel-air adjustment steps after the first.

In some cases, however, the apparatus may be set for one fuel, and thenused to test a fuel so greatly different that during the fuel-airadjustment, the operating limits of the apparatus might be exceeded.According to the present invention this is prevented by an automaticrecycling arrangement. Thus, if during the lowering of the carburetorthe knock intensity increases unduly, indicative of an excessively highinitial carburetor position, arm on pulley 98 will be brought intoengagement with switch 102 causing that switch to close. This completesa recycle circuit from disc 122 through terminal 2 of switch segment A,high limit switch 102, center contact of switch segment B and terminal232. This causes the solenoid 114 to ratchet the sequencer around untilnotch 126 reaches terminal 2, and in passing through position 1, justbefore this, relay is energized through switch segment D to startanother compression ratio search. This new search will end with thefuel-air ratio at a value more suitable for continued automaticadjustment.

Similar recycling also takes place if the knock intensity reaches thesame high value during the carburetor raising at sequencer position 4,if this takes place before the maximum knock search is completed. Insuch a situation the high limit switch 102 is again closed and the samerecycling circuit is completed to return the sequencer to position 2 andanother compression ratio search.

The same safety recycling will take place whenever the knock intensitybecomes excessive, so long as the sequencer is in any position butposition 2. Thus should the sequencer even be in the read-out position(position 7) when a very low octane fuel is added to the carburetor,possible damage from excessive knock will be avoided. It is accordinglynot necessary to reset the apparatus when the fuels are changed. Noautomatic recycling is necessary for position 2 inasmuch as in thisposition the equipment automatically lowers the compression ratio whenthe knock intensity is too high, and such lowering takes place quiterapidly when the knock intensity is very high.

In the combination of FIG. 3 the compression ratio change motor 12 isoperated from the output leads of the deviation reducer by means ofrelays 380, 390. The motor itself is shown as operated by a three-phasepower supply and each relay has three armatures conventionally arrangedto interchange the connections to two leads of the three-phase powersupply and thereby provide reversible motor actuation. A set ofadditional armatures 384, 394 included in each relay is series-connectedin the energizing circuit for the other relay to thereby reduce thepossibility that both relays may inadvertently be operated at the sametime. This result is obtained because energizing one relay opens thecircuit through which the other must be energized.

Another feature of the present invention is the automatic adjustment oftime constant that simplifies and speeds up the use of the apparatus.This is shown more fully in FIG. 7 where a lead 400 from the AC powercircuit to compression ratio change motor 12 controls the time constant.This lead is connected through resistor 402 and rectifier 404 to thewindings 406 of a relay 410 and then to the ground return. The windingsare bridged by a small capacitance 412 to reduce chatter. Relay 410 hasan armature 414 connected to the ground return through the windings 426of a second relay 430. A back contact 416 for armature 414 is connectedto armature 434 of relay 430. A front contact 418 for armature 414 isconnected through an adjustable resistor 420 in the output of rectifier404. A back contact 436 for armature 434 is grounded to the power returnand a front contact 438 for this armature is connected through a smallresistor 450 to the ungrounded end of windings 426. A second armature440 of relay 430 is connected to the power lead 400 and has a frontcontact 442 which returns to ground through windings 456 of a thirdrelay 460. A timing capacitor 452 bridged between contact 416 and itsarmature 414 arranges for the desired energization of relay 460.

When compression ratio change motor 12 is operated, power is suppliedthrough lead 4,00 and actuates relay 410. This pulls armature 414 awayfrom short-circuiting condition with respect to the timing capacitor 452and permits the timing capacitor to charge up through resistor 420,front contact 418, armature 414, capacitor 452, armature 434 and backcontact 436. After about a second or two of charging, the voltage willbuild up to the point where windings 426 are energized to trip relay 430and cause its armature 4.40 to energize the third relay 460. Armature434 will rapidly discharge capacitor 452. The three relays will thenremain in those respective conditions until the power supply to lead 400is interrupted, when all three relays 410, 430 and 460 will bedeenergized.

Relay 460 adjusts the time constant for the knock measurement responseby means of two armatures 461, 462 and a resistor 464. In thedeenergized condition of relay 460, as illustrated, armatures 461, 462merely complete the circuits from an amplifier and rectifier combination470 through a selectable time constant adjusting resistor switchingassembly 480 and through a further DC amplifier 490 so that the finalsignals can be delivered to the deviation computer. The conventionalcircuits can be used for units 470, 480 and 490 as in the standarddetonation meter, Model SG1-iA or Model SG1-AP. These meters are madeavailable to the industry from the Waukesha Motor Co., Fuel ResearchDivision, Waukesha, Wis. Waukesha Drawing L-6613-C gives the completewiring diagram for the above components.

In the construction of FIG. 7, relay armatures 461, 462 are arranged sothat when relay 460 is energized these armatures by-pass the resistorassembly 480 and connect unit 470 to unit 490 through a separateresistor 464, which can have a resistance corresponding to the lowestresistor of assembly 480. With this arrangement the energization ofrelay 460 will assure that the detonation time constant will be thesmallest available regardless of the setting which selector assembly 480may have.

It will be evident from the above that when a compression ratio searchis being conducted and a correcting signal from the deviation reduced isof such long duration that motor 12 must run for more than one or twoseconds, relay 460 is actuated and remains so until the motor stopsrunning. This greatly accelerates the response of the signals suppliedto the deviation computer from the knockmeter and is of considerablevalue in speeding up the automatic measurement as well as reducinghunting. Without the automatic time constant reduction the signals atthe deviation computer may still be responding to the latest compressionratio change when the next compression ratio change is called for. Forvery small compression ratio changes, however, a long time constant canbe tolerated and is even preferred since it gives a more stableindication of a iinal knock intensity.

Although many different circuit constants can be used in the timingarrangement for relay 450, the following have shown very good results.

Resistor 402-1000 ohms;

Resistor 420-minimum 2500 ohms, maximum 5000 ohms;

Capacitor 412-0.25 microfarad;

Capacitor 45280 microfarads;

Resistor 450-100 ohms;

Capacitor 427-030 microfarad.

Also for the circuit of FIG. 3,

Resistor 240 can be of 10,000 ohms; Capacitor 242-010 microfarad;Capacitor 282-080 microfarad; and Capacitor 230-025 microfarad.

Although control slide wire 94 is shown as part of the combination ofFIG. 4, it can be physically located elsewhere and is conveniently apart of unit in FIG. 3. This unit in one practical arrangement is astandard type recorder with a repeater or so-called self-balancing slidewire as in the above-mentioned Minneapolis-Honeywell recorder, or as inU.S. Pat. 3,034,125 granted May 8, 1962.

The sequencer of the present invention need not have the formillustrated in FIG. 3 and a different embodiment is shown in FIG. 8.Here there are two sequence conditions determined by the position of acontrol arm 500 which is pivoted at 504. Movement of the arm around thepivot is accomplished by a pair of solenoid cores 501, 502 actuated byseparate windings and connected together by a rod 506 that has a pin 507engaged in a slot 508 in the arm. Two different windings 511, 521 arearranged to actuate core 501 to move the arm to the counterclockwiseposition in which it is illustrated and where it holds a switch S31closed. A single Winding 512 is arranged to move the arm clockwise to aposition where it holds a different switch 532 closed. Both switches531, 532 are of the normally open type so that they remain open unlessclosed by the arm.

Switch 531 energizes deviation reducing control 24 which can, by way ofexample, be of the type illustrated in FIG. 4. This control in turnoperates a sequence shift 510 as for example when one or severalsuccessive timing pulses of the deviation reducing control produces nocompression ratio increase or decrease signal. For such operation relay310 of the construction of FIG. 4 can have an additional armature thatcloses a switch in a sequence shift energizing circuit each timethyratron tube 301 tires. Switches like 323 and 333, operated by theincrease and decrease tubes 302 and 303 respectively but arranged innormally closed condition, are connected in series in the sameenergizing circuit so that the delivery of either an increase ordecrease signal opens the energizing circuit. The sequence shift isaccordingly not completed until one or more energizing pulses aredelivered to shift unit 510, and indicates that the knock intensity hasreached a predetermined standard value.

Actuation of shift unit 510 causes winding 512 to attract core 502moving the core to the left and thus rotating arm 500 to its clockwiseposition. This opens switch 531, discontinuing the operation of thedeviation reducing control, and closes switch 532 to energize the knockmaximizing control 26. Such control can have a simple time actuated camoperated assembly of switches 541, 542

13 that first lowers the carburetor to the desired minimum fuel-airratio (switch 541), and then raises it in the intermittent mannerdescribed in connection with FIG. 3 (switch 542). Excessive lowering ofthe carburetor can be prevented by using a minimum position switch thatopens the lowering circuit when the desired low level is reached.

Maximizing control 26 is connected to operate a sequence reset unit `522in the event the knock intensity exceeds the preset standard valuebefore the maximum knock condition is reached. This energizes winding511 to return arm 500 to the counterclockwise position in which it stopsthe knock maximizing and starts another compression ratio search throughcontrol 24. In the meantime the knock maximizing unit 26 is returned toits starting position as by a return spring 544 that is overcome by thetiming drive but takes over when the timing is deenergized.

The second compression ratio search in a sequence will generally becarried out with the fuel-air ratio closer to the final desired value sothat at the following knock maximizing step a maximum will be reached atthe standard value. If the standard value is again exceeded, however, athird recycle will be effected and this time the desired maximum shouldbe obtained. Rating indicator 30 is then energized to show and/or make arecord of the compression ratio and/or antiknock rating. This can bearranged to terminate the operation of the apparatus, or else continuethe testing with another fuel sample. In either case rating indicator 30energizes winding 521 to return the apparatus to compression ratiosearch condition. Also it can operate a fuel selector shift valve 546 toautomatically switch the carburetor to a new fuel supply so that theapparatus automatically continues to measure and indicate antiknockratings of dierent samples.

The deviation-reducing control can also have embodiments other thandescribed in connection with FIG. 4. FIG. 9 shows such an alternativemodification which is built around a DArsonval type meter 550 having apointer 552 mounted on a pivoting arrangement 554 and balanced so thatwhen not energized the pointer is held against a left-hand stop 556.Current supplied through lead 558 will then cause the pointer to pivotin clockwise direction away ifrom the stop by an amount corresponding tothe intensity of the current. Instead of or in addition to the usualmeter scale, the meter 550 has a set of arcuate contacts 561, 562, 563,564, 565, 566, 567, 568, 569 and 570 spaced from each other andextending the length of the arcuate path along which the pointer cantravel. Each contact is connected to a separate relay of a set of relays571, 572, 573, 574, 575, 576, 577, 578, 579 and 580.

The pointer 552 is made of metal or other electrically conductivematerial and is connected as by lead 582 so that it completes a commonreturn to the energizing circuits for each of the relays S71 through580. The pointer is normally positioned to move in a plane spaced fromthe plane in which the contacts 561-570 lie. However, the pointer isquite flexible and a contactor arm &1 connected as an armature of anelectromagnet 586 is arranged to bend the pointer over to the plane ofthe contacts whenever the electromagnet is energized. When theelectromagnet is deenergized the contactor is lifted away from thepointer as by a return spring that is not shown.

Each of the relays 571-580 is also connected to close a circuit thatenergizes compression ratio motor 12. The circuits of relays 571-575cause the motor to rotate in the direction that increases thecompression ratio, while those of relays 576-580 cause it to rotate inthe opposite direction. Furthermore relays 575, y576 are arranged todeliver very short pulses of motor-energizing current; relays 574, 577somewhat longer pulses; relays 573, 578 still longer pulses; relays 572,579 pulses that are even longer; and relays 571, 580 the longest pulses.Dashpots or other time delay devices can be used to provide the abovepulse variations. The longer acting relays such as 57'1, 572, 573, 578,579 and S80 can also be connected as by separate contacts to decreasethe time constant-'of the knock ampliication circuits.

The meter 5-50 can be of the general construction available commerciallyunder the name LIAD multi-contact meter-relay from Assembly Products,Inc., Chesterland, Ohio, or Desert Hot Springs, Calif. Its arcuatecontacts can Ibe so located that there is an appreciable space or deadband 588 between the central pair 565, 566, while the spaces between theother contacts are not as wide as the contact on the pointer. The latterspacing will assure that at least one relay will be operated every timethe pointer is pushed into the plane of the arcuate contacts while thepointer is in a rotary position materially removed frorn the dead band588.

The apparatus of FIG. 9 is operated by connecting its lead 558 to theoutput of the knock signal circuit and supplying to its electromagnet586 a uniformly timed succession of identical energizing pulses. Theknock signal circuits and/or movement of the meter 550 are adjusted sothat the dead band 588 delines the standard knock intensity. Theapparatus will then automatically operate to bring the compression ratioof a test engine to the value that produces standard knock intensity.

A feature of the construction of FIG. 9 is that it can be operated withknock signals of the relatively low level used to operate standardknockmeters so that no further amplilication of these signals is needed.In fact meter 550 can even be made to operate with signals in the 1millivolt range or smaller ranges for which some of the standardamplification used with knockmeters can be eliminated.

The knock maximizing arrangements of the present invention need not bemade with a recorder as at in the construction of FIG. 3. The same typeof maximizing means can be used with a pulley 98 or similar rotarymember driven directly by the compression ratio motor 12, as by means ofa drive connection similar to flexible drive 48 in FIG. 2. FIG. 10 showsa different form of knock maximizing device in which two solenoids 601,602 are operated in opposition to each other with a magnetized armature604 polarized with respect to the solenoids so that when equal currentspass through the solenoids the armature is balanced between them. Forthis purpose each solenoid is connected so that current through itcauses it to repel the armature. The armature is pivoted as at 606 andcarries a flag 608 which, when the armature is balanced, will cover twophotoelectric cells 611, 612.

The currents through the respective solenoids 601, 602 are supplied fromseparate amplifiers shown as vacuum tubes 621, 622 having bias circuits631, 632 controlled by an alternating sequencer 634. Signals from theknockmeter are supplied to sequencer 634 which is arranged tointermittently deliver the knockmeter signal to the bias circuits 631,632 in alternate fashion. The sequencer or bias circuits themselves canhave a repeater that develops a bias voltage that varies withthe'knockmeter signal intensity and maintains thatbias voltage betweenthe intermittent sequencer steps. A conventional selfebalancing bridgethat drives a potentiometer tap or slide wire, is suitable for thispurpose.

The apparatus of FIG. l0 is connected to a control that effects theraising of the carburetor bowl as in the intermittent manner describedin connection with FIGS. 3 and 8. At each of the intermittent raisingsteps the alternating sequencer 634 applies the knockmeter signal so asto adjust the bias of one of the bias circuits 631, 632. The nextintermittent step is applied by the sequencer to the other bias circuit.The raising of the carburetor bowl is carried through at least two stepsregardless of the control action of the circuit of FIG. lO. Theknockmeter signals will be slightly higher at each step of the sequencerso that the solenoids 601, 602 will be unbalanced at least for thesecond and subsequent steps so long as the knockmeter readings areincreasing, Accordingly the armature 604 will be deflected to one sideor the other, exposing one of the photoelectric cells 611, 612. Suchexposure is arranged to continue the knock maximizing sequence.

When the knock readings reach a maximum, however,

two successive knock readings will be substantially equal and at thesecond of these steps the armature 604 will be balanced and obscure bothphotoelectric cells. This deenergizes the sequencer to indicate that theknock maximizing search is completed, and if desired to shift to a newcompression ratio search.

Instead of relying on a balancing of the armature, the apparatus of FIG.10 can be arranged so that the alternating sequencer 634 alternatelyconnects the photoelectric cells 611, 612 to control the discontinuanceof the knock maximizing search. With this arrangement increasingknockmeter readings at each step will always cause the armature to berepelled from the solenoid operated at the individual steps. Acorresponding switching of the photoelectric cells will accordinglydevelop alternating search-continuing signals from them. However, when aknock maximum is reached the knock intensity signals will begin todiminish and at the next step the armature will be moved in a directionopposite to that in which it moved during the knock-increasing steps.This movement will be out of step with the switching of thephotoelectric cells so that a photoelectric signal of a different typewill be obtained and will stop further searching.

The mechanical knock maximizer of FIGS. 4, 5 and 6 can also be operatedto stop the maximizing search before the knock intensity signalsdiminish to any significant degree. For this purpose switch nose 252 canbe biased outwardly, that is toward pin 264 by a spring only strongenough to gradually overcome the friction at the mounting pivot 258.With this arrangement rotation of pulley 98 after pin 264 first beginsto depress nose 262, will cause the switch to close, after which thenose bias will rotate the switch around pivot 258 between theintermittent rotary steps of pulley 98. Switch 250 will accordingly beclosed for only a short period of time at each such step. When the knockintensity reaches a maximum, however, the pulley 98 will not advance andwill therefore leave switch 250 open and such open condition can then beused to terminate the knock-maximizing search.

FIG. 11 represents another embodiment of the invention in which agasoline blending is carried out so as to automatically maintain thefinished blend at a preset knock value. At 650 is shown a mixing unitwhich is supplied by a first blending stream through conduit 651 and asecond blending stream through conduit 652. A valve 654 in conduit 652is arranged to vary the rate at which the second stream is fed into themixing unit. The blending stream in conduit 652 can be a standardantiknocking concentrate such as the conventional tetraethyllead with orwithout scavengers and preferably with a stabilizer that keeps thetetraethyllead from decomposing too rapidly as when it is subjected toelevated temperatures. Other additives such as phosphorus-containingcompounds and the like can also be present in the concentrate.

The final blend is withdrawn through conduit 656 and can be supplied todelivery lines, storage tanks, tankers, tank trucks or the like. A smallbleed line 658 is branched off conduit 656 and supplies an auxiliarycarburetor bowl 660 with a small flow of the nal blend. A suction tube662 in the auxiliary bowl 660 is externally threaded so it can be raisedor lowered in bowl 660 as by a manually operated or motor drivenrevolving nut 653 so that the lower tip 655 of the tube establishes thefuel level for feeding fuel to the engine carbuertor jet assembly. Tube662 is raised or lowered to establish the fuel level which results inmaximum knock intensity. A by-pass valve 657 can be opened to draw fuelinto bowl 660 from a source 659 of reference fuel (prototype), ifdesired. A small positive displacement pump 665 creates a suction intube 662 so that all fuel in excess of that required by the engine isremoved from the upper portion of bowl 660.

Conventional carburetor bowl assemblies 666, 667 and 663 along withauxiliary bowl 660 can supply fuel through separate feed lines thatdischarge at a rotary carburetor selector valve 681. Selector valve 681discharges fuel from the selected carburetor reservoir directly to theengine. Bowls 666 and 667 are supplied with the conventional primaryreference fuels used in Calibrating the engine for octane ratings. Bowl663 is supplied fuel from reservoir 659, preferably of a prototypereference fuel of constant composition representing the standard againstwhich the blended stream fuel in line 656 is compared. For automaticblend operation, bowls 666 and 667 need not be used.

Blend control valve 654 can be of the usual remotely controlled typeoperated by an air motor or by an electric motor 700. This motor is ofreversible type with separate windings 701, 702 which determine thedirection of rotation. The windings are energized through a disablingrelay 705 and a control relay 707, by a deviation-reducing control 710which can be like that of FIG. 4 or FIG. 9. In the illustratedconstruction of FIG. 11, the deviation-reducing control 710 includes asetpoint slidewire 745 and a control slidewire 749, as in theconstruction of FIG. 4, with the control slidewire similarly operated inresponse to the knock intensity signals.

A companion reversible motor 720 similar to motor 700 and also withseparate rotation controlling windings 721, 722, is electricallyconnected for operation by a principal relay 708, and motor 720 isphysically connected to operate slidewire 745 to control the setting ofits set-point.

A pair of timers and associated secondary relays and switches areconnected to energize the above relays and to operate carburetorselector valve 681 through an additional reversible motor 730 which hasseparate rotation controlling windings 697, 698. Motor 730 also operatesswitches 781, 782, 791, 792 by rotation of cam 691. A first timer motor731 includes an arm 733 which it rotates downwardly, as seen in thefigure, and which in turn pushes down before it an actuating rod 735that operates two switch blades 737, 739. Both blades are mechanicallybiased upwardly, as indicated, so that blade 737 is normally out ofengagement with its cooperating contact 741 while blade 739 is inengagement with its cooperating contact 743. Lugs 746 and 748 arearranged on actuating bar 735 so that when the arm 733 moves downwardly,blade 737 engages its contact 741 before blade 739 is pushed away fromits contact 743. A solenoid 750 cooperates with arm 733 so that when thesolenoid is energized it pulls that arm up to a. reset limit which marksthe zero point from which timer motor 731 begins operation. Switches752, 756 each normally closed, are also actuated to open condition bythe energization of solenoid 750. Another switch 754 is normally closedbut is mechanically forced open when arm 733 returns to the z'ero point.

A second timing motor 732 is similarly provided with a timing arm 734,actuating rod 736, switch blades 738 and 740, lugs 747 and 749, solenoid751 and switches 753 and 755.

Switches 761, 762, 763, 764, 765 and 766 of the single pole, doublethrow variety, are also shown as connected so that by moving theseswitches to their right-hand positions as shown in FIG. 1l, thecarburetor bowl motor 730 is connected for automatic operation by relays693, 695 and the timers 731, 732 to supply the engine fuel from fuelbowl 663 or from auxiliary bowl 660 as needed. In their left-handpositions switches 761 through 766 place the selector motor 730 underthe sole control of switches 786, 787 to select fuel from carburetors666 or 667 as desired. The direction in which motor 730 then operates isdeter-mined by switches 786, 787.

Operation of the device as a gasoline stream control is effected bypositioning switches 761 through 766 to their right-hand positions asshown in FIG. 11. Closing of the master switch 789 sets the device inoperation. Timers 731, 732 must be positioned manually for the initialstep. Such switch closing also serves to rotate motor 730 to bringselector switch 681 to the proper carburetor bowl. With timer 731 resetand timer 732 in the timed-out position, the deviation reducing control710 delivers correcting impulses as needed to carry the set-point ofslidewire 745 to a position representative of the antiknock rating ofthe reference fuel (prototype). These corrective impulses are deliveredthrough the normally open contacts of relay 708 to motor 720 and are notpermitted to go to motor 7 00.

The timing run of motor 731 can be arbitrarily arranged to occupy aperiod which is adequate for the slidewire 745 to reach its setting. Astiming motor 731 approaches the end of this timing run, it first closesswitch 737, thereby energizing solenoid 751, relay 707 and relay 695.

Solenoid 751 resets timing motor 732 and temporarily opens switch 753.Relay 707 when energized, opens its armatures without delay, but whendeenergized times out through a short delay -before reclosing itsarmatures. This temporarily prevents pulses from deviation reducingcontrol 710 reaching motor 700. Relay 695 supplies power throughswitches 764, 792, 765 to winding 697 of selector motor 730. This poweralso charges condenser 699. Motor 730 will operate cam 691 and thecarburetor selector Ivalve 681, rotating them until cam 691 actuatesswitch 7 92, stopping the ow of motor-energizing current. When switch792 is so actuated, it also closes an auxiliary circuit that permitsdischarge of condenser 699 to the winding 698 which acts as a brake onmotor 730', causing rotation of cam 691 to stop more rapidly. Carburetorselector valve 681 will have thus been positioned on bowl 660 which canthen supply fuel to the test engine. By this time timing motor 731 hasgone a little further and opened switch 739 so that motor 731 isstopped. The current to solenoid 751, relay 707 and relay 695 is alsostopped by then, and switch 753 accordingly closes. Motor 732 then'begins to time out by power supplied through switches 740 and 753. Thispower also passes through switch 756 to relay 708, which in its actuatedposition permits deviation reducing control 710 to send correctingimpulses to motor 700 through the armatures of delay relay 7 07 (afterit has timed out) and through the armatures of relay 705. Relay 705 isarranged to be always actuated whenever the test engine is running, andacts as a safety to assure keeping valve 654 in its last position shouldthe test engine stop.

During the timing run of timer 732, the signals from the deviationreducing control operate valve 654 and adjust the blending flow fromline 652 to the degree required to bring slidewire 749 in balance withslidewire 745. As timer motor 732 approaches the end of its run it firstcloses switch 738, energizing solenoid 750 to reset timer motor 731 andopen switches 752 and 756. It also actuates relay 693 so that motor 730will be operated by means of an energizing circuit through switches 763,791, 766 to winding 698 of motor 730, at the same time chargingcondenser 699. The stopping of motor 730 and cam 691 along withcarburetor selector valve 681 then takes place in a manner similar tthat described above so that the engine will now operate on prototypefuel through bowl 663.

The reason for opening switch 756 when timer 731 is reset is todeactivate relay 708 so that any impulse from deviation reducing control710 that might occur after the engine has ceased to operate on streamfuel from bowl 660 will not reposition valve 654.

The above alternate timing steps are then repeated indefinitely and willadjust the blending to the desired antiknock setting.

The suction tube arrangement of FIG. l1 used to maintain the fuel levelin carburetor bowl 660 is particularly desirable in that it is simple toconstruct and operate, yet

it gives very accurate results. The excess fuel can be sucked from thebowl at a very rapid rate and a rapid fuel ow can accordingly be used sothat changes in the fuel are very rapidly detected notwithstanding thelow fuel consumption of the test engine itself.

If it is desired to operate the engine on primary reference fuels orother fuels through bowls 666 and 667, all of the switches 761 through766 are positioned to their left-hand condition at which time motor 730,cam 691 and carburetor selector valve 681 can be positioned by actuationof switches 786 or 787 to operate the engine on these particular fuels.

Instead of using a rotary selector valve for selecting a fuel supply,other types of arrangements can be made. FIG. 12 shows an arrangement inwhich separate valves are used with the individual carburetor bowls, andare suitably actuated to effect the desired operation. This ligure hasone carburetor bowl 660 for the fuel to be tested and another carburetorbowl 663 for a reference fuel, an overliow 862 being provided forcarburetor bowl 660.

Each carburetor bowl supplies a feed line 871, 872 that discharges tothe engine intake 870. Electrically operated valves 881, 882 in the bowloutow lines 87'1, 872 are arranged to automatically select fuel from theindividual bowls. In addition secondary valves 891, 892 can be connectedto lines 871, 872 so as to drain the respective bowls. Bowl 663 can bekept supplied by a reference fuel of constant composition.

The construction of FIG. l2 operates in a manner analogous to that ofFIG. 11, and similar parts are similarly numbered. A set of controlswitches 851, 852, 853, 854 can be set for automatic or manual operationas shown to actuate individual solenoids 982, 992, 981, 991 for therespective rvalves 882, 892, 881, 891, and a start switch 886 isprovided that also resets timer 731.

Closing of the reset switch 886 sets the device in operation byenergizing solenoid '750 along with solenoid 992 and relay 706. (Allswitches 851, 852, 853 and 854 are first placed in their automatic orleft-hand circuit-closing positions.) The ener-gization of solenoid 750pulls timer arm 733 back to the zero position, thus deenergizing itselfby the opening of switch 754. During the time solenoid 750 is energizedit also opens switch 752, thus keeping timer motor 731 from operating.When solenoid 750 deenergizes itself it permits switch 752 to close,completing an energizing circuit for timer motor 731 through switch 739.This motor-energizing circuit also actuates solenoid 982 to hold valve882 open. In the meantime reset switch 886 has been released so thatsolenoid 992 (along with relay 706) has become deenergized, permittingvalve 892 to close. Accordingly carburetor bowl 663 which had beendrained through valve 892 while it was open, is now permitted to feedfuel through valve 882 which is opened to the test engine when timermotor 731 starts running. During this operation of the test enginedeviation reducing control 710 delivers correcting impulses as needed tocarry the set-point of slidewire 745 to a position representative of theantiknock rating of the reference fuel (prototype). Relay 708 isenergized so that the correcting impulses are delivered to motor 720 andnot to motor 700.

The timing run of motor 731 can be arbitrarily set at a period which isadequate for the slidewire 745 to reach its setting. As timing motor 731approaches the end of this timing run it first closes switch 737,thereby energizing solenoids 751 and 991 as well as disabling relay 705.Solenoid 751 thereupon resets timing motor 732 while solenoid 991 opensthe drain for bowl 660. Solenoid 751 is promptly locked out by thereturn of timing arm 734 to zero position, and timing motor 732 thenbegins its run. By this time timing motor 731 has gone a little furtherand opened switch 739 so that it is stopped, valve 882 is closed andrelay 708 is deenergized.

At the commencement of timer motor 732, valve 881 is opened and relay707 is energized. The test engine is accordingly switched to fuel frombowl 660 while further deviation reducing signals from control 710 aredelivered to motor 700 rather than motor 720. Such signals will nowoperate valve 654 and adjust the blending flow from line 652 to thedegree required to bring slidewire 794 in balance with slidewire 745.

As timer motor 732 approaches the end of its run it first closes switch738 which resets timer motor 731 and opens drain valve 892. A littlelater timer riiotor 732 opens switch 740 thereby reaching the end of itsrun and completing the switch-over to the reference fuel. I

The above alternate timing steps are then repeated iridefinitely andwill adjust the blending to the desired antiknock setting. Relays 705and 706 can be of the type that when energized, immediately open theirswitches but o nly permit the switches to close after some' delay.'.1`his time delay can be arranged to span the transition period whilethe fuel shifting is being accomplished up to'the time when the new fuelhas stabilized itself in the engine intake system.

The apparatus of FIG. ll (or FIG. l2) can be used with a knockmaximizing control and appropriate sequencer where absolute knock valuesare to be attained. In such event, an automatic or manual check can bein ade of the set-point of slidewire 745 to make sure that it. iscorrectly positioned for the reference fuel. If it is incorrect then theapparatus needs adjustment, generally to compensate for the driftnormally experienced with test engines as they operate. The resetting ofthe set-points of slidewire 745 by such an automatic or manual check issufficient compensation in itself, where the resetting is of smallextent.

The apparatus of FIG. ll (or FIG. l2) can also be used to merely checkcompression ratios with or without a check of fuel-air ratios. To thisend the signals delivered to the slidewires 745 and 749 can correspondto the height of the test engine cylinder in its compression ratioadjustment travel, and can be obtained from a differential transformerhaving a core movable with respect to. windings, and coupled to theengine so as to move with the compression ratio adjustment. The windingswill show a mutual inductance that varies with the height of the core,and thus will deliver a signal representative of the cornpression ratio.The set point of slidewire 745 can also be displaced from the positionrepresented by the compression ratio, as by adding to or subtractingfrom the compression ratio signal a value corresponding to a differencethat is to be maintained between the fuel being monitored or blended anda reference fuel. This enables the monitoring or blending to beconveniently carried out with a reference fuel which is not a targetfuel but has an antiknock value somewhat off the target value. It is preferred in such a modification to have the compression ratio signalsdelivered through a spanning potentiometer having a uniform electricaltaper so that a specified degree of potentiometer adjustment representsthe same antiknock difference everywhere along the potentiometer. Afixed signal similarly adjusted can then be readily added to orsubtracted from the output of the spanning potentiometer to provideaccurately adjustable operation.

The reference fuel used can be a preformed sample of blend from line656. When the blending ingredient fed through line 652 is added in onlysmall proportions, as for example when it is the above-mentionedantikriock concentrate, it does not significantly affect the fuel-airratio required for the final blend to exhibit its maximum knock, and thepreformed batch of reference fuel will have substantially the samemaximum knock fuel-air ratio regardless of the blending proportions. Atthe very first timing run the apparatus can be set for that ratio eithermanually or automatically, and for each timing run after that it issufficient merely to adjust the blend so that it requires the samecompression ratio as the reference fuel (Prototype) to reach the sameknock intensity. Because no draining of the reference fuel is neededwith such an arrangement, as pointed out above, the total quantity ofreference fuel needed can be relatively small for a blending operationof long duration. Further decreased in the amount of reference fuelneeded can be arranged by adjusting the timer so that two or more finalblend tests are made after every reference fuel test.

It is helpful to have sampling line 658 as short as convenient tominimize the flow rate required through it in order for the fuel in bowl660 to match that in line 656. At the same time the connection from thesampling line 658 to outfiow line 656 can be placed down-stream of valve654 close to the mixing unit 650 so that automatic blending adjustmentsare promptly detected.

Where the streams fed through lines 651 and 652 are streams of differentrefinery products such that varying mixtures of them will show maximumknock at different fuel-air ratios, the apparatus of FIG. 11 (or FIG.12) can be expanded to include the entire test assembly of FIG. 3 withthe sequencer automatically reset by the timer motors 731, 732. Also thecarburetor bowls 660 and 663 can in this arrangement have their heightsseparately adjustable so that the adjustment of one to maximum knockwill not affect the adjustment of the other.

One highly practical arrangement is to have the automatic fuel-air ratioadjustment connected to automatically go through one such adjustmentwhen a blending control is initiated, the blending control thencontinuing indefinitely with only the compression ratio or the knockintensity automatically controlling the blending. In the event of aprocess upset or other significant change in any of the refinery streamsfed to the blender, there is ample notice and the blending controlapparatus can be manually or automatically re-initiated so that anotherfuel-air ratio search is effected. If desired the apparatus can bearranged to go through two fuel-air ratio searches when it is placed inoperation, one such search for the 'blend fuel and the other such searchfor the reference or prototype fuel. During the remainder of theblending control, which can extend for many days, the apparatus canmerely control the blending to -keep the compression ratio at thedesired level when the engine is operating on the blend fuel, with anoccasional shift to the reference or prototype fuel to check on thedesired compression ratio level.

It may also be desirable to apply a positive temperature control to thefuel fed to the test engine, as for example to compensate for heating bythe valve solenoids 881, 882, 891 and 892. The continuous operation ofone of these solenoids usually generates appreciable heat. The fuellines adjacent these solenoids, or the solenoids themselves, mayaccordingly be jacketed with liquid ow passages through which iscirculated a cooling liquid such as water or overow fuel. Themotor-driven rotary selector valve of FIG. 11 does not need cooling.Cooling is also helpful to reduce evaporation of the lighter fractionsof the fuels and the measuring errors that can thus result. A smallrefrigerating unit is particularly helpful and can keep the fuelssupplied at a substantially constant low temperature.

The reading of the control slidewire 794 with or without that ofslidewire 745, can be shown in a display window as described above inconnection with FIG. 2, or it can be printed out, photographed, orrecorded as by continuous or intermittent recording. It can also betransmitted to remote locations for monitoring purposes. Analog ordigital forms of the readings can be used for such transmission, and ifdesired digital forms can even be used for the control operations.

The sequencers of the present invention provide for each controlfunction or step to go to completion regardless of the time required formoving to the next position and control function. Also at each step theswitching action will take place without unnecessarily extending thetime required for a given control function. Different 21 fuels orgasolines react at different rates to changes in compression ratio and/or fuel-air ratio, and the sequencers of the present invention make thevarious adjustments as quickly, if not more quickly, than is possiblemanually.

The sequencer of FIG. 3 can also be connected to a fuel selector shiftmechanism that shifts the supply of fuel to the engine 10 from onesource to another, as for example by having a separate bowl and floatvalve combination for each source. One convenient form of shiftmechanism includes a multi-position rotating plug selector valve linkedto a stepping solenoid and arranged so that when the sequencer reachesposition 7 it delivers a pulse of current to the solenoid and causes thevalve to step around a circular path. At each step the selector valvecloses one supply line and opens another. Six or eight steps or more canbe provided in this circular path before the valve returns to itsoriginal position so that a corresponding number of fuels can beselected automatically. One or more of the fuels can be a reference fuelhaving a known antiknock rating so that the opera tion of the equipmentcan be checked.

It is a feature of the present invention that because the apparatus willoperate automatically, it can in any measurement be arranged to gothrough as many sequences as necessary to reach a standard knockintensity as accurately as desired. By increasing the accuracy of thisprocedure, the need for comparison with standard fuels is greatlydiminished. Occasional comparisons of this type will still be desirablein order to indicate when the engine or other components have driftedaway from the desired operating characteristics and need correction ormaintenance. Setting the high limit switch just above but close to thestandard knock intensity position will materially increase the accuracy.

As discussed above, very good automatic knock measurement is obtainedwith the compression ratio correction pulses that increase in length asthe knock intensity signals depart further from the desired standard. Anexactly proportional variation between the correction pulse length andthe departure from standard, so that doubling the departure doubles thepulse length, is highly effective but the pulses can increase in lengthfaster or slower than this. It is preferred, however, that the pulselength increase at least about 10% as fast as the signal departures fromstandard, and that they increase no more than about twice as fast as thedepartures, inasmuch as this range provides most rapid automaticoperation with little or no hunting and with signal intensity checksmade as frequently as one per ten seconds. Other checking frequenciescan also be used to advantage, particularly with the higher rates ofpulse length variation as compared to signal strength changes.

Carburetor level raising is best accomplished in small steps about to 10seconds apart and preferably about 8 seconds apart, although the stepscan be as little as onetenth millimeter and as much as five-tenthsmillimeter each. The length of time taken for each step should be heldto the minimum, preferably not over two seconds.

The above conditions apply both to the antiknock testing as with theapparatus of FIG. 3, as well as to the simpler compression ratioadjustment desired as a preliminary step to use of the apparatusillustrated in FIG. 1l.

The apparatus of FIG. 11 (or lFIG. l2) can also be arranged to controlthe operation of refinery units such as alkylation, platforming,hydroforming, reforming, catalytic cracking, etc., instead of blending.By connecting motor 700 so that it adjusts the critical controls to suchapparatuses in accordance with the test measurements, they can bepositioned to produce fuel stocks of the required antiknock quality.When making a test on a fuel, it is helpful to make sure that all gasbubbles are removed from it before it reaches the set level. Flowingstreams are more apt to contain such bubbles, and the venting of thebowl 660 effectively removes them.

Instead of using an electrically energized motor to directly operate theblending valve, the motor can merely operate an air valve that raisesthe air pressure in a control conduit. This conduit can then be used tocontrol an air-operated blending valve. Because of the greater safetyinherent in air operation for valves in a refinery or blending unit,this type of control is very desirable. Additional blending details areset forth in application Ser. No. 377,192, the entire contents of whichare incorporated herein.

It is also desirable to compensate antiknock rating or comparisonresults in accordance with variations in barometric pressure. This canbe accomplished by merely having a recording of the barometric pressureat the time each test is carried out. Barometric pressure recording canbe separately made by conventional barographs and any correction appliedby separate calculation from the rating results expressed in compressionratio figures, or in the micrometer setting or compression ratioindication of the cylinder which is the value officially listed in theASTM Manual.

As an alternative technique, the air intake for the test engine of thepresent invention can be arranged to be supplied with air at thestandard barometric pressure so that no correction is needed and therating is then read directly from the compression ratio indicated by therating indicator of the apparatus. For this purpose the air intake ofthe test engine is connected to a compartment of fairly limited size,which compartment in turn is open to the outside air pressure through alimited passageway. A barometric switch in the compartment is connectedwith a damper or the like to throttle down the opening to the outsideair pressure whenever the pressure in the compartment rises abovestandard. The compartment is also in communication with the dischargeend of a blower which is actuated to increase the pressure within thecompartment when the barometric switch shows that the pressure withinthe compartment is falling below standard.

When air at standard barometric pressure is used it will be advisable topressurize the fuel reservoirs and sight glasses to the same degree toprevent discharge of the fuel from vent holes.

The deviation-reducing control of the present invention can have formsother than those referred to above. The deviation can, for example, becomputed mechanically as by causing the detonation signals to compress aspring balanced by a second spring which is given a predeterminedstandard compression, a pole of a double-throw switch being held betweenthe springs so that it trips in a different direction, depending uponwhich of the spring compressions is the greater one. Magnetic balancingcan also be similarly effected.

The various types of apparatus described above can be made resistant tocorrosive and other harmful environ'- ments as by potting the entirewiring in a chemically resistant resin such as an epoxy resin, or bysoldering the wiring with silver solder or similar highlycorrosion-resistant compositions.

Obviously many other modifications and variations of the presentinvention are possible in the light of the above teachings. It is,therefore, to be understood that within the scope of the appended claimsthe invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A method for determining the difference in octane quality between aprototype gasoline of known octane quality and a test gasoline ofsimilar composition but of unknown quality which comprises passingalternately said test and prototype gasolines through a spill-typecarburetor of low gasoline holdup into a,E standard ASTM knock enginewhile maintaining a constant air-to-fuel ratio adjustment, measuringalternately the knock intensities of said gasolines, and converting theengine-knock intensities alternately obtained from .the'two gasolinesinto a difference in octane quality between said gasolines.

2. A method for determining the difference in octane quality between aprototype gasoline of known octane quality and a test gasoline ofsimilar composition but of unknown quality which comprises passingalternately said test and prototype gasolines through a fuel chiller toadjust said gasolines to substantially the same temperature, passingalternately said chilled gasolines through a spilltype carburetor of lowgasoline holdup into a standard ASTM knock engine while maintaining aconstant air-tofuel ratio adjustment, measuring alternately the `knockintensities of said gasolines, and converting the engineknockintensities alternately obtained from the two gasolines into a dilerencein octane quality between said gasolines.

3. A method for determining the difference in octane quality between aprototype gasoline of known octane quality and a test gasoline ofsimilar composition but of unknown octane quality which comprisespassing alternately said test and prototype gasolines through a fuelchiller to adjust said gasolines to substantially the same temperature,passing alternately for periods said chilled gasolines through aspill-type carburetor of low gasoline holdup into a standard ASTM knockengine while maintaining a constant air-to-fuel ratio adjustment,measuring alternately the knock intensities of said gasolines with aSOI-A detonation meter having a time-controlled switch for switchingfrom a smaller to a larger time constant at the desired time in eachperiod, and converting the knock intensity measurements into adifference in octane quality between said gasolines.

4. A method for continuously controlling the octane quality of a linegasoline for spark-ignition engines which comprises passing alternatelysaid line gasoline and a prototype gasoline of composition similar tothe line gasoline and of known octane quality through a spill-typecarburetor of low gasoline holdup into a standard ASTM knock enginewhile maintaining a constant air-to-fuel ratio adjustment, measuringalternately the knock intensities of said gasolines converting the knockintensities alternately obtained from the two gasolinesinto a differencein octane quality between the line and prototype gasolines, andautomatically taking corrective measures to adjust the octane quality ofthe line gasoline where the dilerence in octane quality between line andprototype gasoline exceeds a specified limit.

5. A method for continuously controlling the octane quality of afinished commercial gasoline at the point at which the gasoline stocksand antiknock additive are blended which comprises passing alternatelythe iinished commercial gasoline coming from the blender and a prototypegasoline of composition similar to the nished gasoline and of knownoctane quality through a fuel chiller to adjust said gasolines tosubstantially the same temperature, passing alternately said chilledgasolines through a spill-type carburetor of low gasoline holdup into astandard ASTM knock engine while maintaining a constant airto-fuel ratioadjustment, measuring alternately the knock intensities of saidgasolines, converting the knock intensities alternately obtained fromthe two gasolines into a difference in octane quality between theprototype and finished gasoline, and automatically changing blendingconditions where the difference in octane quality exceeds a specifiedlimit.

6. An octane comparator for determining the difference in octane qualitybetween a prototype gasoline of known octane quality and a test gasolineof similar composition but of unknown octane quality comprising meansfor alternately supplying the prototype and test gasolines according toa programmed time cycle to a single spill-type carburetor of low fuelholdup, means for controlling the temperature of both the prototype andtest gasolines so they enter the carburetor at substantially the sametemperature, means for alternately measuring the knock intensities ofsaid prototype and test gasolines in a standard ASTM knock engine, andmeans for converting said knock 24 intensities into a difference inoctane quality between said prototype and test gasolines.

7. An octane comparator for determining the difference in octane qualitybetween a prototype gasoline of known octane quality and a test gasolineof similar composition but of unknown octane quality comprising meansfor alternately supplying prototype and test gasolines for a time periodon each gasoline to a single spill-type carburetor of low fuel holdup,means for controlling the temperature of both the prototype and testgasolines so they enter the carburetor at substantially the sametemperature, means for alternately measuring the knock intensities ofsaid prototype and test gasolines in a standard AS'FM knock engine,means for averaging the knock-intensity measurements with a long timeconstant so that the knock-intensity measurement is in effect an averageof preceding engine cycles, means for alternately measuring the knockintensities of each gasoline only at the desired time in each period,and means for converting said knock intensities into a difference inoctane quality between said prototype and test gasolines.

8. An octane comparator for continuously controlling the octane qualityof a line gasoline for spark-ignition engines comprising means foralternately supplying said line gasoline of unknown octane quality and aprototype gasoline of known octane quality and composition similar tosaid line gasoline to a single spill-type carburetor of minimum fuelholdup, means for controlling the temperatures of both the prototype andtest gasolines so they enter the carburetor at substantially the sametemperature, means for alternately measuring the knock intensities ofsaid prototype and line gasolines on a standard ASTM engine, means forconverting said knock intensities into a difference in octane qualitybetween said prototype and test gasolines, and means for automaticallyadjusting the octane quality of the line gasoline where the differencein octane quality between line and prototype gasoline exceeds aspecified limit.

9. An octane comparator for continuously controlling the octane qualityof a nished commercial gasoline at the point where lead alkyl is blendedwith the gasoline stock comprising means for alternately supplying thecommercial gasoline-lead alkyl blend of unknown octane quality and aprototype gasoline of known octane quality and composition similar tothe commercial gasoline to a single spill-type carburetor of minimumfuel holdup, means for controlling the temperatures of both theprototype and commercial blended gasolines so they enter the carburetorat substantially the same temperature, means for alternately measuringthe knock intensities of said prototype and commercial blend gasolineson a standard ASTM engine, means for converting said knock intensitiesinto a difference in octane quality between said prototype andcommercially blended gasolines, and means for adjusting blendingconditions where the difference in octane quality between line andprototype gasoline exceeds a specified limit.

10. An apparatus for monitoring the knock characteristics of a stream offuel, said apparatus including a detonation testing engine, a measuringsystem connected to indicate the intensity of detonation knocking thattakes place in the engine and adjusting mechanism connected forautomatically adjusting the compression ratio of the engine to keep thedetonation intensity at a predetermined value, sampling means connectedto receive samples of fuel and deliver them to the engine for continuouscombustion therein at maximum knock fuel-air ratio, the sampling meansbeing further connected to deliver to the engine samples of a referencefuel for continuous combustion therein at maximum knock fuel-air ratio,the adjusting mechanism being connected to cause the sampling means toautomatically shift from one fuel to the other and back again. i

11. The combination of claim 10 in which the adjusting mechanism is alsoconnected to automatically bring the

